- Essential Factors
The Essential Factors model [http://www.intersafe.com.au/essentialSafety.html] [Geoff McDonald & Associates Pty Ltd, HAZARD EVALUATION USING ESSENTIAL FACTORS METHODOLOGY, May 1991] [Vidmark Productions Limited, THE ESSENTIAL FACTORS OF ACCIDENTS] is an incident investigation model based on determining the essential and contributory factors that lead to an incident. An incident is viewed in terms of an interaction of essential and contributing factors that results in damage to people, property or production. An essential factor is one which when removed from, or added to, an incident sequence will interrupt that sequence. A contributing factor is one which increases the likelihood that the sequence of factors will continue but is not essential to the damage.
Every incident has essential factors associated with people, equipment and environment giving the 100% paradigm.
100% / 100% / 100% paradigm –
o 100% of incidents include “people” factors
o 100% of incidents include “equipment” factors
o 100% of incidents include “environment” factors
Determining essential factors is assited by the use of the
Analysis Reference Tree Trunk (ART-T). Essential factors occur over the incident sequence, which basically consists of stable, meta-stable and unstable periods leading up to the damage.It is the purpose of the Essential Factors model to attempt to use value neutral language [Ergonomics Society of Aust. ed (1994) ERGO WEEK 1994, INVESTIGATION FOR PREVENTION, UNDERSTANDING CONTRIBUTORY FACTORS: MYTHS VS REALITY, PH&Assoc, Qld.] to give maximum “meaning” and minimum “affect”. This will not always be the case but it is suggested that the use of the word “cause” and “human error” by an accident investigator during data collection and interview phases, will have a potentially greater negative response than the use of alternative words. Those alternative words can be value neutral in terms of:
o what did or did not occur,
o what people did or did not do,
o what they knew or didn’t know,
o what skills they had or did not have,
o what equipment was present or absent,
o what information was the machine detecting or not detecting,
All essential factors are equally important in continuing the incident sequence, but they differ in controllability. Each essential factor, once identified is able to be reviewed for potential points of control. That is potential ways in which to reduce the risk of that incident re-occuring.
This approach was developed by Geoff McDonald and is based on William Haddon's work see
Haddon Matrix .
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